Restrictive flow regulating valve and control circuit employing same

ABSTRACT

The restrictive flow regulating valve has a plug which is adjustable axially of a complementary valve sleeve to expose different lengths of a slot in the plug, dependent on the adjusted position of the plug, for predetermining different basic flows. The plug and sleeve have a lapped fit. Concentricity of the plug and sleeve is assured during valve assembly by driving the plug into the sleeve while the sleeve is held in the valve body for limited radial movement with its passage normal to the plug axis so that the plug itself moves the sleeve into coaxial relation with the plug. The sleeve is then secured in coaxial relation in the body while so held by the plug. The valve is incorporated in an electro-mechanically operated hydraulic control circuit which controls the cycling of a cutting machine for rapid advance to feed starting position, and slower advance during feed and, optionally, for successive increments of the feed by which the tool cuts progressively deeper into the workpiece, each increment of feed being followed by rapid withdrawal of the tool to clear the chips and each withdrawal being followed, in turn, by a rapid advance to just short of the beginning of the next increment of cut. The entire control is mounted on the machine itself so that it can remain fully installed relative thereto hydraulically and electrically if the machine is to be moved to a new worksite.

United States Patent [1 1 Swatty Dec. 25, 1973 RESTRICTRVE FLOWREGULATING VALVE AND CONTROL CIRCUIT EMPLOYING SAME [75] Inventor:Eugene E. Swatty, Euclid, Ohio [73] Assignee: Fluid Controls, Inc.,Mentor, Ohio [22] Filed: Aug. 16, 1971 [21] Appl. No.: 172,137

[52] US. Cl 137/613, 137/6253, 251/208 [51] lint. Ci. F16k 31/143 [58]Field of Search 251/120, 121, 361, 251/208; 137/613, 625.3

[56] References Cited UNITED STATES PATENTS 3,349,798 10/1967 Allenl37/625.17

694,773 3/1902 Morris 251/361 2,160,582 5/1939 Brugma 137/613 X3,120,243 2/1964 Allen et a1. 137/6253 X 3,506,242 4/1970 Aunspach251/361 3,511,470 5/1970 Beckett et a1 251/121 Primary Examiner-Irwin C.Cohen Attorney-John Harrow Leonard [57] ABSTRACT The restrictive flowregulating valve has a plug which is adjustable axially of acomplementary valve sleeve to expose different lengths of a slot in theplug, dependent on the adjusted position of the plug, for predeterminingdifferent basic flows. The plug and sleeve have a lapped fit.

Concentricity of the plug and sleeve is assured during valve assembly bydriving the plug into the sleeve while the sleeve is held in the valvebody for limited radial movement with its passage normal to the plugaxis so that the plug itself moves the sleeve into coaxial relation withthe plug. The sleeve is then secured in coaxial relation in the bodywhile so held by the plug.

The valve is incorporated in an electro-mechanically operated hydrauliccontrol circuit which controls the cycling of a cutting machine forrapid advance to feed starting position, and slower advance during feedand, optionally, for successive increments of the feed by which the toolcuts progressively deeper into the workpiece, each increment of feedbeing followed by rapid withdrawal of the tool to clear the chips andeach withdrawal being followed, in turn, by a rapid advance to justshort of the beginning of the next increment of cut.

The entire control is mounted on the machine itself so that it canremain fully installed relative thereto hydraulically and electricallyif the machine is to be moved to a new worksite.

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RESTRICTIVE FLOW REGULATING VALVE AND CONTROL CIRCUIT EMPLOYING SAMEBACKGROUND 1. Field of the Invention Restrictive flow regulating valveand machine tool hydraulic control employing the valve.

2. Description of Prior Art Precision restrictive flow regulating valvesand uses thereof in hydraulic control circuits are known in the art. Theprior types of valves are very costly to manufacture, particularlybecause of the difficulty of obtaining true concentricity of the valveplug and the complementary sleeve or seat in the valve body.

The prior control circuits employing flow control valves areunnecessarily complicated and expensive, and are subject tomalfunctioning, due to some extent to the prior types of regulatingvalves employed.

Further, prior hydraulic controls have been arranged in cabinets orenclosures located adjacent to the machine to be controlled. Thesecontrols generally require partial disassembly, reassembly, andreadjustment whenever the machine is moved to a new worksite.

Such controls have been used for drill presses. In general, in drillpresses, the drilling operation for a shallow cut requires but a singleadvance and retraction of the drill. For deeper drilling operations, oneor more socalled steps are required in which the drill is fed onlypartway of the full depth of cut at each step, then is retracted toremove the chips, and then is again advanced in the next succeeding stepto cut progressively deeper.

The advances and retractions usually are arranged so that on the firstadvance the drill is moved rapidly to starting position in which thepoint of the tool is at, or closely adjacent to, the surface of theworkpiece to be drilled. The drill is driven more slowly on the feedingor cutting stroke at a rate determined by the rotary speed, type ofmetal, diameter and type of drill, and the like, and then is retractedrapidly entirely out of the partially drilled bore to remove the chips.It is next advanced rapidly almost to the bottom of the preceding cut,and then fed at cutting speed into initial contact with the bottom ofthe partially drilled bore for initiating the next drilling cut. It isthen fed at the usual cutting feed speed and again fully retracted, andso on through as many successive cuts and chip removing operations asmay be necessitated by the particular drilling operation.

For purposes of illustration, the valve and control are shown inconnection with a conventional drill press and are arranged so as tocause, in preselected cycles, a succession of progressively deeper cuts,each out being followed by a full retraction of the tool for chipremoval.

One of the principal objects of the present invention is to provide arestrictive flow regulating valve which can be produced economically,and to a method of manufacturing the same, which assures extremeprecision in alignment of the valve plug and its complementary valvingsleeve and seat.

A more specific object resides in the provision of anelectro-mechanically controlled hydraulic circuit which includes thevalve and can be set to repeat preselected operating cycles rapidly andaccurately.

Various other objects and advantages of the present invention willbecome apparent from the following description wherein reference is madeto the drawings, in which:

FIG. 1 is a top plan view of a restrictive flow regulating valveembodying the principles of the present invention;

FIG. 2 is a fragmentary longitudinal sectional view of the valve and istaken on the line 2-2 of FIG. 1;

FIG. 2A is an enlarged fragmentary sectional view of a portion of thevalve illustrated in FIG. 2;

FIG. 3 is a fragmentary cross sectional view of the valve taken on theline 3-3 in FIG. 2;

FIG. 4 is a diagrammatic perspective view of the hydraulic drive and themechanical control elements and electrical switches of the control forcontrolling the drive of a drill press, the press being showndiagrammatically therein in dash lines for purposes of illustration;

FIG. 5 is a hydraulic diagram illustrating the hydraulic control circuitof the present invention;

FIG. 6 is a schematic wiring diagram showing the electrical controlcircuit of the present invention; and

FIG. 7 is a diagrammatic illustration of a cycle of successive cuts,showing the relation of the successive starting positions of the drill.

Referring first to FIGS. 1 and 2, the restrictive flow regulating valveV of the present invention comprises a body 1 having an inlet bore 2communicating with an internal bore 3 which, in turn, through a valvingmechanism, communicates with a coaxial internal bore 4 of smallerdiameter than the bore 3. The bore 4, in turn, is connected to an outletbore 5 such that, when the valve is open, hydraulic fluid can flow fromthe inlet bore 2 out through the outlet bore 5 under the control of thevalving mechanism.

Mounted in the bores 3 and 4 is a removable sleeve element 6 offrusto-conical shape having near its larger base a peripheral radialflange 7 of which the end faces are in parallel planes normal to theaxis of the sleeve element.

The element 6 has a basal extension which projects a short distance intothe bore 3 when the flange 7 is secured in operating position. At oneface, the flange 7 seats on an annular shoulder 8 at the juncture of thebores 3 and 4 and normal to their common axis. Thus the shoulder 8, byengagement with the flange 7, holds the element 6 with the axis of itsfrusto-conical portion parallel to the common axis of the bores 3 and 4.

The element 6 is held in place in the body by an externally threadedheader plug 9 which is in threaded engagement with internal threads inthe bore 3, the joint being sealed by an O-ring, as illustrated. Theplug has a cavity 10 at its inner end and lateral passages 11 connectingthe cavity with the bore 3. The liner end of the plug 9 engages thatface of the flange 7 which is opposite from the shoulder 8 and holds theflange firmly seated against the shoulder 8 in metal to metal contact.The shoulder 8 and adjacent face of the flange 7 are preferablyprecisely ground or lapped for assuring that they can provide a tightmetal to metal seal and can hold the sleeve element 6 with its axisparallel to the axis of the bores 3 and 4. For this purpose, the element6 is made of hardened steel which can be lapped to an extremely precisepolished finish.

Mounted in the plug 9 for movement axially thereof to open and closedpositions is a settable valve member, indicated generally at 12. Thevalve member 12 comprises an externally threaded stem 13 which is inthreaded engagement with an internally threaded bore 14 in the plug 9and which extends outwardly beyond the outer. end of the plug 9 andcarries on its outer end a knurled adjusting knob 15. Rotation of theknob in opposite directions advances and retracts the valve member 12axially of the bores 3 and 4. The valve member 12 is provided with anO-ring seal 16 between its ends for preventing the escape of pressurefluid through the bore 14.

The valve member 12 has a valve plug 20 which is coaxial with, andintegral with, the stem 13. The plug 20 is cylindrical and tits into acoaxial bore 21 through the smaller base of the element 6. The plug 20fits the wall of the bore 21 with a precise lapped fit so close that itprevents the passage of liquid between the exterior peripheral surfaceof the plug 20 and the wall of the bore 21, as is described hereinafter.

The plug 20 has an internal dead-end bore 22 having its open end at theinner end of the plug 20. One or more longitudinal extending radialslots 23 are provided in the plug 20 and extend through its peripheralwall and open throughout most of its length into the bore 22, thusforming a passage through the valve when the plug 20 is retracted to anydegree from its closed position.

The member 12 has a frusto-conical seat 24 with its smaller base at theouter end of the cylindrical plug 20 and of the same diameter as theplug 20. As the valve plug 20 is moved to closed position, the seat 24seats against the wall of the outer open end of the bore 21 and therebycloses the bore 21. The slots 23 extend from the inner open end of theplug 20 a substantial distance lengthwise of the plug, but terminate alittle short of the inner end of the seat 24.

By rotating the operating knob 15 in opposite directions, selectively,the plug 20 can be advanced to fully extended position in which the seat24 is in sealed position and cuts off entirely the flow of any liquidthrough the valve, and to retracted positions wherein the liquid flowsfrom the inlet 2 through the slots 23 into the dead-end bore 22 andtherefrom through the bore 4 to the outlet 5. The size of the passagefor liquid is determined by the length of that portion of the slots 23exposed in the hollow inner end of the plug 9 for receiving liquid fromthe bore 3. In the fully retracted position of the plug 20,. the slots23 are ample to accommodate a relatively free flow of liquid from theinlet 2 to the outlet 5.

An important feature of the valve is the precise fit of the plug 20 inthe bore 21. As mentioned, the element 6 and plug 20 are made ofhardened steel. During manufacture the cylindrical surface of the plug20-is ground precisely to shape and diameter. The wall of the bore 21,beginning at its entrance end and extending for about ten thousandths ofan inch in a direction toward its outlet end is cylindrical andpreferably about one thousandth of an inch smaller in diameter than thecylindrical surface of the plug 20. Beyond this short cylindricalportion of its wall, the bore is frusto-conical, expanding very slowlyin the direction away from the entrance end toward the bore 4. Thecylindrical surface of the plug 20 and entrance portion of the wall ofthe bore 21 are then lapped to a precise co-axial fit.

Here it is to be noted that heretofore great difficulty has beenexperienced in making such a cylindrical plug surface and the surface ofits receiving sleeve bore precisely coaxial. While this can be done byconventional methods, such as polishing the plug exteriorly of the bodyto a shape and size for. fitting a polished bore wall in fixed positionin the valve body, the operation is slow and expensive, and even whenextreme care is exercised, a large number of rejects customarily resultfrom lack of precise shape and concentricity.

In accordance with the present invention, the plug 20 and the entranceportion of the wall of the bore 21 are lapped together to a precise fitbefore both the plug 20 and element 6 are installed in the body 1. Theelement 6 is then placed in the bore 3 with the flange 7 resting inmetal to metal contact against the shoulder 8 between the bores 3 and 4and with the entrance end of the bore 21 facing the plug 20. The plug 9,with the valve stem 13 threaded therein, and with the plug 20 inadvanced position relative to the plug 9 is screw-titted into the bodybore 3. With the plug 20 in advanced po-' sition, its cylindrivalsurface is pushed partly into the lapped entrance portion of the bore 21of the element 6 before the plug 9 has engaged the flange 7 sufficientlyto cause any appreciable resistance to shifting of the element 6radially.

Since the element 6 can shift radially and since the cylindrical surfaceof the plug 20 and the entrance wall of the bore 21 have been lapfitted, before this assembly, to precise roundness and diameter, theplug 20 will shift the element 6 radially in the body so that thecoacting cylindrical entrance wall of the bore 21 and the cylindricalwall of the plug 20 are precisely coaxial. While the element 6 is heldby the plug 20 in this condition, the plug 9 is screwed farther into thebody so that its inner end engages the flange 7 and clamps the flangefirmly in position between the inner annular end of the plug 9 and theshoulder 8, thus securing the element 6 in a position in which theentrance wall of the bore 21 is exactly concentric with the plug 20.

The bore 21 and open end of the bore 22 communicate with passages 25 inthe element 6. The passages 25 communicate with the bore 4 andtherethrough with the outlet bore 5.

The structure thus far described provides for adjustment for preselectedbasic flows, determined by the setting of the plug 20 axially by theknob 15.

In addition to this selective adjustment, the flow through the valve isautomatically varied within certain limits by the differential inpressure between the inlet 2 and outlet 5. For this purpose a piston orspool 30 of hardened steel is mounted in the bore 4 for reciprocationendwise thereof. The spool 30 is urged to a retracted position in thebore 4, as illustrated in FIG. 2, by means of a spring 31 which issupported on a suitable pin 32 connected in fixed coaxial relation withthe element 6.

In order to render the valve responsive to the pressure of fluid in theinlet 2, the inlet is connected by coaxial communicating bores 33 and 34and a lateral duct 35 with the bore 4 at the outer or head end of thespool 30. Thus hydraulic pressure fluid entering through the bore 35drives the spool 30 to the left in FIG. 2 against the force of thebiasing spring 31. The biasing spring 31 is selected as to strength fora given working range of pressures in connection with which the valve isto be used. The bore 4 has. an outlet port 37 which opens into the bore5 to the left of-the spool 30 when the spool 30 is fully retracted, asillustrated in FIG. 2. When the pressure in the inlet 2 exceeds apreselected minimum, it forces the spool 30 to the left in FIG. 2. Asthe pressure progressively increases above the minimum; the spool is'driven progressively furtherto the left. thus covering progressivelymore of the port 37 and thereby progressively reducing the effectivepassage for fluid from the bore 4 through the outlet bore 5.

MECHANICAL CONTROL STRUCTURE The mechanical control structure isillustrated diagrammatically in FIG. 4, and comprises a rigid support orpanel 40 having reinforcing channels 41 secured to its rear face andhaving a front mounting panel 42 secured in forwardly spaced relationfrom the forward face of the support 40 by means of suitable bolts andspacers, such as indicated at 43. The support 40 also includes an endplate 44 to which main power cylinder 45, for advancing and returningthe drill, is secured by suitable bolts 46. A piston 47 is reciprocablein the cylinder 45 and has a piston rod 48 extending through a suitablehold in the plate 44. A rack 49 is connected to the outer end of the rod48 and is slidably secured on the support 40 for movement endwiseparallel to the piston rod 48. The rack 49 is in driving engagement witha pinion 50. The pinion is mounted on, and for rotation with, a shaft 51carried by the support 40. As is well known in the art, the drill press,indicated generally at 52, has a shaft 53 with a radial handle 54 bywhich the shaft 53 can be rotated for advancing and returning the quill.The shaft 51 is connected to the shaft 53 for co-rotation therewith. Theshaft 53 carries a pinion 55 which is drivingly connected to a rack 56on the spindle quill 57 of the press for advancing the quill downwardlyfor rapid advance and for feeding, and for retracting it upwardly forchip removal and to starting position.

The cylinder 45 is provided at opposite ends with pipes 58 and 59,respectively, by which the cylinder is connected in a reversiblehydraulic circuit for extending and retracting the piston 47 and therebythe rack 49.

As best illustrated in FIG. 4, a mechanical memory mechanism isprovided. This mechanism comprises a cam bar 60 which is connected by asuitable bracket 61 to the rack 49 and is mounted in a guide slot on thesup- 7 port 40 for movement endwise of, and in fixed position relativeto, the rack 49. Slidably mounted on the cam bar 60 is a memory dog 62.In order to prevent accidental shifting of the dog 62 on the bar 60 bylight noncontrol forces, a suitable spring biased frictional drag shoe,not shown, may be mounted within the dog 62 and bear against a face ofthe cam bar 60. The spring strength is such that the dog 62 can remainin fixed position relative to the cam bar while performing its switchoperating operations, but can be moved for resetting by imposing forcesthereon greater than required for switch operation.

The cam bar 60 is provided with a plurality of lateral bores 68 arrangedin a row which extends lengthwise of the cam bar 60. The bores 68 openthrough the forward face of the bar 60 so as to receive, selectively, atrip pin 69. The bores 68 are preferably internally threaded, as is thereceived end of the pin 69, so that the pin can be screwed into thebores 68, selectively, and thereby held fixedly in position in theselected bore. The pin 69 is for stopping the rapid return of the quillwhen the point of the drill is returned to the original startingposition in which the drill point is at or close to the surface of theworkpiece into which a bore is to be drilled, and for initiating thestart of the quill on its rapid advance stroke to the cut startingposition for the next increment of cut.

The dog 62 has a longitudinal slot 70 through its forward wall to affordrelative passage of the dog 62 and pin 69 as the dog is slid along thecam bar 60. A pin 71 is mounted on the front panel 42 in a preselectedposition in which it engages a finger on the memory dog 62 and arreststhe travel of the dog 62 with the cam bar 60 when the piston has moved apredetermined distance to the right in FIG. 4 from fully extended towardre- 1 tracted positions.

Here it is again noted that for advancing the quill 57, the piston 47 ismoved on its retracted direction, to the right in FIG. 4, thus movingthe rack 49 and cam bar 60 to the right. It is also to be noted that asthe piston is retracted, in FIG. 4, the memory dog 62 is carried to theright by and with the cam bar 60 until the finger of the dog 62 strikesthe pin 71, whereupon movement of the dog 62 is arrested while the cambar 60 continues to move to the right. The piston 47 is extended to theleft in FIG. 4 to retract the quill 57, for removing chips from a borebeing drilled before making the next successive drilling cut. Upon thesubsequent retraction of the piston to advance the quill 57, the quillwill be advanced rapidly to a new position, determined by the newposition of thedog 62, for starting the next successive cut, and thenwill be fed at a slower rate during cutting. The successive positions ofthe memory dog 62 and certain limit switches and control elements to bedescribed hereinafter assure the proper successive starting positions ofthe drill, when the bore being drilled is so deep that it must bedrilled progressively deeper by a succession of increments of feed eachof which is followed by complete withdrawal of the drill to removechips.

Generally, as indicated in FIG. 7, the control is arranged so that eachrapid advance of the quill ceases when the drill point has closelyapproached, but has not reached, the surface of the work on the firststep, or the bottom of each partially drilled bore produced by apreceding feed step after the first step, and is followed by a slowercutting feed beginning just before the drill point finally engages thebottom of the partially drilled bore. This prevents jamming of the drillby too rapid an advance as it starts a cutting operation.

Mounted on the panel 42 are limit switches LS1, LS2, and LS3,respectively. A limit switch LS4 is adjustably mounted on the drillpress and is operated by the quill 57, when the quill is fully advancedto the full final depth of cut, in the single cut cycle or the final cutof the successive cut cycle.

Also mounted on the panel 42 in parallel relation to the path of the cambar 60 is a rock bar 75 which is supported by suitable brackets 76 forrocking movement about its axis and for limited movement endwise. Therock bar 75 carries a reset finger 77 for resetting of the memory dog 62to its original starting position after a complete cycle. The bar 75also carries a trip 78 which in the normal unrocked position of the baris arranged to be engaged by the trip pin 69 for causing the rock bar toactuate the limit switch LS2 for terminating the return of the quill 57when the tool point has been withdrawn just beyond the surface of theworkpiece. The rock bar 75 is biased to the right in FIG. 4 by means ofa coil spring 79. The reset finger 77 and trip 78 are adjustableindividually endwise of the rock bar 75, by sliding them along the bar75 to selected adjusted positions, and securing them in the selectedpositions by conventional set screws, not shown.

As the quill 57 starts to return from cutting position, the cam bar 60is driven to the left and the rock bar 75 is in a normal unrockedposition in which the trip 78 is in a position to be struck by the pin69 and the reset finger 77 is out of the path of the dog 62.Accordingly, upon initiation of each of the successive cutting stepsafter the first one, the dog 62 remains in the position on the cam bar60 to which it was caused to be moved by the pin 71 during the precedingfeed step.

When the pin 69 strikes the trip 78, it drives the rock bar 75 to theleft, closing the switch LS2, which stops the return of the quill 57with the drill point withdrawn from the bore it has cut to a locationjust beyond the work surface. Concurrently, the closure of the switchLS2 restarts the rapid advance of the quill, the termination of whichand the start of feed are controlled by the dog 62 and the switch LS3.The difference in the distance between the pin 71 and the position ofthe limit switch LS3 relative to the position of the dog 62 is chosen soas to stop the rapid advance of the quill 57 at a location short of theworkpiece so that the drill assumes its slower feed advance beforestriking the work.

Thus, the termination of the original rapid advance and the start of thefeed are controlled by the coaction of the dog 62 and the switch LS3, asare the termination of the rapid advance and the start of feed for eachsuccessive cut of the cycle. The different position of the quill atwhich each successive feed is started in successive cutting cycles isdetermined by the new position to which dog 62 has been moved by the pin71 upon the termination of the immediately preceding cut.

Upon rocking the rock bar 75 to its rocked. position, the reset finger77 is moved into the path of the memory'dog 62 and arrests its movementto the left with the cam bar 60 so that the dog 62 is restored to itsoriginal starting position when the quill 57 reaches fully returnedposition.

For thus restoring the dog 62 in its initial starting position for thenext cycle during the final return of the quill 57, the bar 75 is rockedby a linkage 80, driven by a solenoid 81 which is controlled bya controlrelay, to a positionto place the reset finger 77 in the path of the dog62 while moving the trip 78 out of the path of the trip pin 69, thusoverriding the switch LS2.

After thus restoring the dog 62, to its original position, the rock bar75 remains in its rocked position with the trip 78 out of the path ofthe pin 69 so that the rack 49 continues moving to the left in FIG. 4,until it operates the switch LSI and thereby stops the entire operationwith the quill restored to its original starting position for a repeatcycle.

Before describing the electric and hydraulic circuitry in detail, it iswell to review the functions of the limit switches.

The limit switch LS1 is'in a position to be engaged I and operated bythe free or left hand end of the rack The limit switch LS4, asmentioned, is operated by the quill 57 itself, when the quill is fullyadvanced, to start the full return of the quill to its original startingposition.

The limit switch LS3 is operated by the dog 62 as the dog is carried tothe right by the cam bar 69, thus terminating the rapid advance of thequill and starting the dwell and slower feed advance.

HYDRAULIC ClRCUIT The hydraulic circuit employed in the control is shownschematically in FIG. 5. Forprecise operation, it includes therestrictive flow regulating valve V hereinbefore described in detail.

In this hydraulic circuit, the piston and cylinder assemblage isreversible. The pipeline 59 is connected to the head end of the cylinder45 and the pipeline 58 to the rod end.

The pressure fluid is supplied by a variable delivery, pressurecompensated pump P driven by a motor M. The output of the pump isdelivered through a line 82 to a normally closed solenoid operatedhydraulic stop and reversing valve 83. The valve 83 is reversibleselectively by an advance solenoid 83a and a return solenoid 83b. Areturn line 84 leads from the valve 83 to a sump S. Leading from thereversible discharge and return ports of the valve 83 are lines 85 and86, respectively. The line 85 is connected to the inlet of a check valve87, the outlet of which is connected to the line 58, and thereby to therod end of the cylinder 45. The outlet of the valve 87 is also connectedto the inlet 88a of a regenerating circuit valve 88 having an inlet8821, an outlet 88b, and a plug 89 which is normally spring seated toclose the inlet 88a, but which can be unseated by a predeterminedpositive differential in pressure at the inlet 88a. The valve 88 isconnected by a line 90 to the line 85 in by-passing relation to thecheck valve 87 so that the plug 89 is subjected to full line pressure oris vented to the sump S, depending upon the setting of the valve 83. Theend of the plug 89 subjected to fluid from the line 90 is larger thanthe seatingarea of its opposite end which normally closes the inlet 88a.

When the solenoid 83a is energized, the valve 83 connects the pressureside of the pump P to the line 85 and the sump S to line 86. With thissetting, the valve 88 is closed due to its biasing spring and the fullline pressure delivered through the by-pass line 90. Concurrently, livefluid is delivered to the rod end of the cylinder 45 and return fluid isreturned from the head end of the cylinder 45 to the sump S. This returnis through the lines 59 and 86 and, selectively, by way of therestrictive flowvalve V and a normally open solenoid operated valve 91augmented by a limited small concurrent flow through the valve V.

The valve 91 is normally open and is closed by energization of asolenoid 9.10 to constrain all of the return flow to pass through thevalve V which has its inlet 2 connected to the line 59 and its outletconnected to the line 86.

With the valve 91 open and the solenoid 83a energized, the piston 47 isdriven to the right, advancing the quill rapidly, until the rapidadvance is interrupted, by closure or reversal of the valve 83, orbottoming of the piston 47 in the head end of the cylinder 45, orclosure of the valve 9.1 by energization of its solenoid 91c.

Generally, this rapid advance is terminated and the feed initiated byenergization of the solenoid 91c, the valve 91 thereupon being set toblock the return flow therethrough so that all of the return flow mustpass initially through the restrictive flow valve V by which the returnflow is retricted and controlled. Thus, with a relatively free returnflow through the valve 91, rapid advance of the quill to feed startingpositions is effected, and upon closing of the valve 91 by energizationof its solenoid 91c, the rapid advance is terminated and slower advanceof the quill for feed is effected by the valve V.

Starting with the valve 83 in OFF position, the operation is initiatedby energization of the advance solenoid 83a so that the valve 83connects the line 82 to the line 85, whereupon pressure fluid issupplied through the check valve 87 to the rod end of the cylinder 45 todrive the piston 47 to the right for rapid advance of the quill.Concurrently the valve 83 connects the head end of the cylinder 45 tothe sump S primarily through the normally open valve 91 which by-passesmost of the return fluid around the restrictive flow control valve V. Toinitiate the slower advance or feed of the drill, the valve 91 is closedby energization of the solenoid 910. While the solenoids 83a and 910 areenergized, the rate of feed of the tool is controlled by the rate ofdischarge from the head end of the cylinder 45 permitted by therestricted flow valve V. Any tendency toward acceleration of the piston47 to the head end of the cylinder which would result in an increasedreturn flow of fluid through the valve V and acceleration of the quillfeed, causes the spool 30 to move against the force of its biasingspring 31 and reduce the effective size of the orifice 37, therebyconstraining the piston and quill from acceleration and assuringconstant feed speed.

If, at the completion of the feed stroke, the solenoid 83a isdeenergized, the valve 83 returns to its normally closed position inwhich all flow to the rod end of the cylinder 45 from the pump P and thereturn to the sump S are stopped. The electric circuit is arranged toprovide for dwell in any stopped position.

If the return solenoid 83b is then energized, the valve 83 is operatedto reverse the flow of pressure fluid therethrough. If the solenoid 91is then deenergized, the valve 91 returns to its open position. Uponthis energization of the return solenoid 83b and reversal of the valve83, the line 86 is connected to the pressure side of the pump P and theline 85 is connected to the sump S. The flow from the pump P is then tothe head end of the cylinder 45, a slight flow passing through the valveV and the main flow through the valve 91. The check valve 87 is seatedto prevent return of fluid from the rod end of the cylinder 45.

Consequently, the return flow from the rod end of the cylinder 45 isthrough the line 58, to the inlet of the valve 88, thus unseating theplug 89 and connecting the line 58 to the inlet of the valve 91 and tothe outlet of the valve V, and both the valve V and valve 91 areconnected by the line 59 to the head end of the cylinder 45. Since thevalve 91 is now open, the rod end of the cylinder 45 is connected to thehead end. As a result, pressure fluid from the pump P and return fluidfrom the rod end of the cylinder 45 are commingled and fed to the headend of the cylinder, and both ends of the cylinder are subjected tosubstantially the same fluid pressure. The rod 48 is of sufflcientdiameter so that the total pressure exerted on the head end of thepiston 47 is greater than the total pressure exerted on the rod end.This positive differential in pressure on the head end drives the piston47 to the left, thereby driving the quill 57 on its rapid return stroke,which stroke requires but little power. The circuit is, therefore,regenerative, and a much more rapid operation of the piston is obtainedthan would be possible with a like pump delivery were the return fluidfrom the rod end of the cylinder returned to the sump S.

Thus the adjustment of the position of the valve plug 20 determines therate of flow through the restricted flow regulating valve V, and hencethe rate of return flow from the head end of the cylinder 45, andthereby the rate of advance of the quill.

ELECTRICAL CONTROL CIRCUIT A schematic wiring diagram, shown in FIG. 6,is used to control the sequence of operations to provide the selectedsteps of the cycles desired. Its functioning is best understood by adescription of it in connection with the cycles of operation.

SINGLE CUT CYCLE WITH FULL RETURN For initiating this operation, anormally open pushbutton PB is closed, thereby establishing thefollowing circuits:

a. through the normally closed contact 2CR1 of a control relay 2CR, thenormally closed contacts TR2a of a timing relay TR2 and the coil of acontrol relay 1CR, thus closing the normally open contacts 1CR1 toprovide a holding circuit around the pushbutton PB, and opening thenormally closed contacts 1CR2 and closing the normally open contacts1CR3 of the control relay lCR; and

b. through the contacts LS4(1) of the limit switch LS4 for energizingthe advance solenoid 83a and thereby setting the valve 83 for advance ofthe quill 57, the solenoid 83a being maintained in energized conditionthrough the holding circuit. Thereupon, live fluid is supplied to therod end of the cylinder 45.

Since the valve 91 is open to vent the return fluid free to the sump S,the quill 57 is advanced rapidly toward its feed starting position inwhich the drill will be close to the surface of the work. This positionis predetermined by the dog 62 engaging and closing the limit switchLS3. During this entire single cut cycle the normally open limit switchLS2 remains open.

When the dog 62 closes the switch LS3, the solenoid 91s of the feedvalve 91 is energized and closes the valve 91, thereby directing all ofthe return flow from the head end of the cylinder 45 through therestrictive flow valve V and consequently stopping the rapid advance ofthe quill 57 and cbncurrenty initiating the slower cutting feed of thequill. The rate of cutting feed is determined by the rate of this returnflow.

The closure of the limit switch LS3 also energizes the coil of a timingrelay TR1 which starts the cutting time. For a single cut cycle, thistimer is preset for a longer time than that required for the full cutand consequently it does not time out during the cycle. It thereforeperforms no timing function for a single cut cycle, but remainsenergized until deenergized by opening the limit switch LS3.

However, until the timing relay TR1 times out, its normally closedcontacts TRla and TRlb remain closed. The closed contacts TRla establisha holding circuit by-passing the normally closed contacts 2CR1 of acontrol relay 2CR so as to maintain the coil of the relay lCR energizedwhen the contacts 2CRl subsequently open. The contacts TR16 establish acircuit through the now closed contacts 1CR3, the normally closedcontacts TR2b of a timing relay TR2, to energize the coil of the controlrelay 2CR.

Energization of the coil of the relay 2CR (a) opens its normally closedcontacts 2CR (l) which leaves control of the energization anddeenergization of the control relay lCR to the normally open contactsLS4(2) of the limit switch LS4, the normally closed contacts TRla, andthe normally closed contacts TRZa of the timing relay TR2; and (b) openits normally closed contacts 2CR2 so as to prevent energization of theoverride solenoid 81 through the normally closed limit switch LS1. Thiseliminates rocking of the rock bar 75 while the limit switch LS1 isclosed so that the pin 69 cannot strike the trip 78 and operate thelimit switch LS2.

As the quill 57 is advanced on its cutting or feed stroke, it causes thelimit switch LS4 to operate its contacts LS4(1) so as (a) to deenergizethe advance solenoid 83a, thereby stopping advance of the quill 57, (b)to start the timing relay TR2 which starts a dwell time at the end ofthe feed stroke, and (c) to cause the contacts LS4(2) to close andestablish a holding circuit for the coil of the control relay lCRthrough the contacts TRZa so that th control relay lCR remains energizedThough the limit switch LS1 remains closed, the contacts lCR(2) remainopen, so the solenoid 83a remains deenergized.

At the timed dwell period, the timing relay TRZ times out, openingtemporarily its normally closed contacts TR2a, thereby deenergizing thecoil of the control relay lCR whereupon its normally open contacts lCRlreopen to break the holding circuit around the normally open pushbuttonPB.

Since limit switch LS2 has been overridden, it has remained in itsnormally open condition and consequently has not established a holdingcircuit around the push button PB.

Concurrently with the temporary opening of its normally closed contactsTR2a, the timing relay TR2 opens temporarily its normally closedcontacts TRZb, deenergizing the coil of the control relay ZCR.

Deenergization of the coil of control relay 2CR recloses its normallyclosed contacts 2CR1, thus restores the by-pass around contacts TRla andrecloses its normally closed contacts 2CR2 to reconnect the solenoid 81for energization to rock the bar 75 to position the trip 78 out of thepath of the pin 69 so as to override the operation of the limit switchLS2, and reopens its normally open contacts 2CR3 to open the holdingcircuit around the contacts 1CR3 to open the holding circuit around thecontacts 1CR3 and TRlb, to the normally closed contact TR2b and the coilof the control relay 2CR.

The coil of the control relay lCR remains energized so that its normallyclosed contacts 1CR2 are held open. Concurrently the return solenoid 83bcannot be energized. When the coil of the control relay lCR isdeenergized by opening of the contacts TR2a temporarily after dwell, itsnow open contacts 1CR2 reclose. Since the limit switch LS1 is closed,reclosure of the contacts 1CR2 energizes the return solenoid 83b,extending the piston 47 to the left to drive the quill 57 on its returnstroke.

The return of the quill 57 continues until the rack 49, moving to theleft in FIG. 4, strikes and opens the limit switch LS1 and deenergizesthe return solenoid 83b. At this time the quill 57 is fully returned toits original starting position.

Since the by-pass circuit around the pushbutton PB is open, the openingof the limit switch LS1 terminates the single cut cycle which can berestarted only by closing the pushbutton PB.

Since the timing relay TRI was timed for a period longer than a one cutcycle, the normally closed contacts TRla remain closed and the normallyopen contacts TRlb remain open. The normally closed contacts TR2a, whichwere opened temporarily by the timing relay TR2 have reclosed. Thecircuitry is therefore in readiness to restart the cycle on closure ofthe pushbutton PB.

It is to be noted that during the cut, the dog 62, after striking thepin 71, was prevented from moving to the right in FIG. 4 with the bar60. However, during movement of the bar 60 to the left during retractionof the quill 57, the bar was rocked by the solenoid 81, due to reclosingof the normally closed contact 2CR2, to move the reset 77 into the pathof the dog 62 with the bar 60 and thus restores the dog to its originalstarting position on the bar 60 so that the next rapid advance fromfully returned position of the quill 57 will be terminated and thesingle feed step begun with the drill point at the original feedstarting point close to, but not in contact with, the work surface.

MULTI-STEP CYCLE WITH SUCCESSIVE PROGRESSIVELY DEEPER CUTS WITHRETRACTION OF TOOL FROM WORKPIECE FOR CHIP REMOVAL AFTER EACH FEED STEPIn this cycle, the quill 57 is advanced rapidly to bring the drill pointclose to the original work surface, and the feed is then initiated, inthe same manner as in the case of the single cut cycle.

However, the timing relay TR] is set for a timing interval for afraction only of the complete cut so that the quill, after the drill haspenetrated the work for a preselected depth, is returned rapidly untilits point is slightly out of the bore, but near the original worksurface, thus removing the chips. Upon reaching this location, a rapidadvance step is started and continues until the drill point is close to,but spaced from, the bottom of the portion of the bore drilled in thepreceding step. Thereupon the feed is initiated and the bore is drilledmore deeply, followed by a dwell and then return of the drill point tothe same position slightly out of the bore.

These successive steps are continued until the bore is drilled to thefull depth whereupon the quill is returned fully to its originalstarting position.

These steps are indicated specifically in FIG. 7.

At the end of the first cutting step, when the drill has cut thepreselected depth, the timing relay TRl times out, (a) tempoarilyopening its contacts TRla; (b) and temporarily closing its normally opencontacts TRlb. The coil of the control relay lCR remains energizedthrough the normally closed contacts 2CR1 and now closed contacts TR2a,so as (a) to retain normally open contacts lCR(l) closed to establishthe holding circuit around the pushbottom PB, (b) to retain the normallyclosed contacts lCR(Z) open so that the return solenoid 83b remainsdeenergized; and (c) to retain the normally open contacts LCR3 closed toestablish a circuit through the closed contacts TRlb and tr2b and thecontrol relay 2CR. This energizes the coil of the control relay 2CR, (a)closing its contacts 2CR3 to establish a holding circuit by-passing thecontacts 1CR3 and TRlb;

b. opening the normally closed contacts 2CR2 so that the solenoid 81 isdeenergized and the rock bar 75 is unrocked; and

c. opening its normally closed contacts 2CR1.

Since the timing contact TRla is open, as also is the limit switchcontact LS4(2), the opening of the contacts 2CR1 deenergizes the controlrelay lCR, whereupon its normally closed contacts lCR2 are closed.Therefore, the return solenoid 83b is energized and the quill 57 isdriven on its return stroke.

Since the rock bar 75 is unrocked, the trip 78 remains in the path ofthe pin 69. Accordingly, the return continues until the pin 69 strikesthe trip 78, driving the rock bar 75 to the left and closing thenormally open limit switch LS2. Closure of the limit switch LS2reenergizes control relay 1CR through the normally closed contacts 2CR1and the closed contacts TR2a. This immediately opens the normally closedcontacts 1CR2 to deenergize the return solenoid 83b and closes thenormally open LS3, energizing the solenoid 910 to set the feed valve 91to start the feed.

Here it is to be noted that the dog 62 has not been restrained frommovement with the bar 60 to the left during the previous return stroke,and hence remained in the position on the bar 60 to which it had beenmoved by the pin 71 during the preceding feed stroke. Therefore, it doesnot trip the limit switch LS3 and start the feed until the drill pointhas advanced almost to the bottom of the portion of the bore cut by thepreceding cut, as the dog was driven to the left relative to the bar 60to this position of the quill on the first cut. Upon closure of limitswitch LS3 the timing relay TRl is again energized.

The feed continues, as with the first cut, until the next depth of cutselected has been reached and the timing relay TRl has timed out again.Meanwhile, as

before, since at the end of the return of the quill 57 c after thepreceding cut, the limit switch LS2 had been closed and the controlrelay lCR energized by way of the contacts 2CR1 and contacts TR2a. Thisagain establishes the holding circuit through contacts lCRl and opensthe circuit through LCR2 to the return solenoid 83b to stop the returnand energizes the advance solenoid to restart the rapid advance of thequill.

This succession of cuts is repeated until the limit switch LS4 isoperated to energize timing relay TR for timing dwell and stop, and toestablish a holding circuit to the control relay lCR until the timingrelay TR2 times out andopens the contacts TRZa and deenergizes thecontrol relay lCR. Thereby the normally closed contact 1CR2 closes,again energizing the return solenoid 83b to return the quill. When thetiming relay TR2 times out, both control relays lCR and 2CR aredeenergized, so the return solenoid 83b remains energized until the rack49 opens limit switch LS1 and stops the cycle with the quill 57 in fullyreturned position. The repetitive incremental cycle is restarted byclosure of the pushbutton PB.

As mentioned, cyclic controls for machines generally are mounted infloor supported cabinets which require detachment and partialdisassemblage for removal from the machine if the machine is to be movedto a different work site.

In the present instance the support 40 is connected to a bracket 92which, in turn, is bolted in fixed position on the frame or housing ofthe drill press.

The bracket 92 together with the housing of the shaft 51 of the pinion50 and shaft 53 of the press, support the entire control as a unitarypart of the whole so that the press can be moved to different work siteswithout disturbing the control Having thus described my invention, Iclaim:

1. A restrictive flow regulating and control valve mechanism comprisinga hollow body having a first bore and a coaxial second bore, said bodyhaving an internal annular shoulder at the juncture of said bores andwith an end face facing toward the outer end of said first bore andnormal to the axis thereof;

said first bore having an inlet and said second bore having an outlet;

a seat member in the first bore, and having a flow passage therethrough,a portion of said passage having a cylindrical wall with its axisparallel to the common axis of the bores;

said seat member having an external radial annular flange coaxial withthe cylindrical wall and of less diameter than said first bore, one endof the flange facing toward, and being engageable with, said shoulderand the other end of the flange facing toward the outer end of saidfirst bore, the end faces of the flange being parallel to each other andnormal to the axis of the cylindrical wall;

a header plug mounted in and closing the outer end of said first boreand adjustable to different positions axially thereof, and having acentral axial stem receiving bore;

a valve plug member in the first bore and cooperable with the seatmember for controlling the flow through the flow passage and having acylindrical portion interfitting precisely in coaxial slip-fittingsealing relation with said cylindrical wall when the valve plug and seatmembers are in installed condition in the body;

a stem on the valve plug member mounted in said central axial bore foraxial movement relative to said header plug and to said seat member;

clamping means in said first bore and movable with said header plugaxially of said first bore to predetermined axially adjusted positions,and having an inner end portion aligned axially of the bores with saidflange, which inner end portion, in one of said axially adjustedpositions, is disposed close to, but slightly spaced axially from, saidopposite end of the flange while said one end of the flange rests onsaid shoulder, thereby to hold the seat member in the first bore forlimited movement relative to the body radially of the axis of said boresso that the seat member can be shifted radially to permit precisecoaxial relation of its cylindrical wall with said cylindrical portionof the valve plug member by introduction of the cylindrical portion ofthe valve plug member thereinto;

said clamping means being operative, when moved additionally toward saidshoulder, to engage said opposite end face of the flange and clamp theflange in sealing relation against said shoulder in fixed axial andradial position relative to said bores while the cylindrical portion ofthe valve plug member is in said precise interfitting coaxial relationwith said cylindrical wall of said seat member; said cylindrical portionof the valve plug member having passage means therein connecting thebores and provided with inlet means which are open through the outercircumferential wall of said cylindrical portion and positioned so thatthe inlet means are progressively decreased in effective size by saidcylindrical wall as the cylindrical portion of the valve plug member ismoved progressively farther axially in a direction toward said secondbore; wherein said passage means and inlet means comprise an axial deadend bore in the cylindrical portion of the valve member and open at theinner end of the valve plug member, and at least one narrow radial slotextending lengthwise of the cylindrical portion for the major portion ofthe length of the cylindrical portion and extending radially throughsaid cylindrical portion from the outer surface of the cylindricalportion into said dead end bore,

a piston in the second bore and reciprocable axially thereof, andoperative as it is moved from a retracted position to an extendedposition axially of the second bore to progressively restrict saidoutlet;

a spring biasing the piston to said retracted position;

and

said body having a duct continuously connected with said inlet of thefirst bore and connected to the second bore at a location between theouter end of the second bore and outer end of the piston so as tosubject the piston continuously to the fluid pressure at said inlet forvariably biasing the piston thereby toward its extended position againstthe force of the spring in relation to inlet pressure.

UNI'HED STATES PATENT nwm:

CERTWIQATE 0F CORRECTION Patent No. 3,7 ,7 5 Dated D c mb r 5, 973

Inventor(s) Eugene E. Swatty It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Col. 2, line 52, for "liner" read --inner---. I

Col. 3, line 18, for "longitudinal" read --longitudinally--;

line 36, for "sealed" read --se.aling--.

Col. L, line 16, for cylindrival".read -cylindrical--.

Col. 6, line'l3, read --the piston 1+? is moved'in its retractingdirection, to the. I

Col. 8, line 6, for numeral "69" read -60--.

Col. 9, line 6, for "retricted" read --restricted- Col. 11, line 3, for"T1216" read --TRlb--; line 28, for

"th" read --the--.

Signed and sealed this 12th day of November 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents )RM PO-105O (10-69) USCOMM-DC GOING-P69 h u s GOVVERNMINT rnmvmcOI'IICI ID. o-au-su

1. A restrictive flow regulating and control valve mechanism comprisinga hollow body having a first bore and a coaxial second bore, said bodyhaving an internal annular shoulder at the juncture of said bores andwith an end face facing toward The outer end of said first bore andnormal to the axis thereof; said first bore having an inlet and saidsecond bore having an outlet; a seat member in the first bore, andhaving a flow passage therethrough, a portion of said passage having acylindrical wall with its axis parallel to the common axis of the bores;said seat member having an external radial annular flange coaxial withthe cylindrical wall and of less diameter than said first bore, one endof the flange facing toward, and being engageable with, said shoulderand the other end of the flange facing toward the outer end of saidfirst bore, the end faces of the flange being parallel to each other andnormal to the axis of the cylindrical wall; a header plug mounted in andclosing the outer end of said first bore and adjustable to differentpositions axially thereof, and having a central axial stem receivingbore; a valve plug member in the first bore and cooperable with the seatmember for controlling the flow through the flow passage and having acylindrical portion interfitting precisely in coaxial slip-fittingsealing relation with said cylindrical wall when the valve plug and seatmembers are in installed condition in the body; a stem on the valve plugmember mounted in said central axial bore for axial movement relative tosaid header plug and to said seat member; clamping means in said firstbore and movable with said header plug axially of said first bore topredetermined axially adjusted positions, and having an inner endportion aligned axially of the bores with said flange, which inner endportion, in one of said axially adjusted positions, is disposed closeto, but slightly spaced axially from, said opposite end of the flangewhile said one end of the flange rests on said shoulder, thereby to holdthe seat member in the first bore for limited movement relative to thebody radially of the axis of said bores so that the seat member can beshifted radially to permit precise coaxial relation of its cylindricalwall with said cylindrical portion of the valve plug member byintroduction of the cylindrical portion of the valve plug memberthereinto; said clamping means being operative, when moved additionallytoward said shoulder, to engage said opposite end face of the flange andclamp the flange in sealing relation against said shoulder in fixedaxial and radial position relative to said bores while the cylindricalportion of the valve plug member is in said precise interfitting coaxialrelation with said cylindrical wall of said seat member; saidcylindrical portion of the valve plug member having passage meanstherein connecting the bores and provided with inlet means which areopen through the outer circumferential wall of said cylindrical portionand positioned so that the inlet means are progressively decreased ineffective size by said cylindrical wall as the cylindrical portion ofthe valve plug member is moved progressively farther axially in adirection toward said second bore; wherein said passage means and inletmeans comprise an axial dead end bore in the cylindrical portion of thevalve member and open at the inner end of the valve plug member, and atleast one narrow radial slot extending lengthwise of the cylindricalportion for the major portion of the length of the cylindrical portionand extending radially through said cylindrical portion from the outersurface of the cylindrical portion into said dead end bore, a piston inthe second bore and reciprocable axially thereof, and operative as it ismoved from a retracted position to an extended position axially of thesecond bore to progressively restrict said outlet; a spring biasing thepiston to said retracted position; and said body having a ductcontinuously connected with said inlet of the first bore and connectedto the second bore at a location between the outer end of the secondbore and outer end of the piston so as to subject the pistoncontinuously to the fluid pressure at said Inlet for variably biasingthe piston thereby toward its extended position against the force of thespring in relation to inlet pressure.